package com.lagou.edu.factory;

import com.lagou.edu.pojo.Account;
import com.lagou.edu.utils.TransactionManager;
import com.lagou.homework.annotation.Autowired;
import com.lagou.homework.annotation.Component;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.*;
import java.util.stream.Collectors;

/**
 * @author 应癫
 * <p>
 * <p>
 * 代理对象工厂：生成代理对象的
 */
@Component
public class ProxyFactory {

    @Autowired
    private TransactionManager transactionManager;

    public void setTransactionManager(TransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }

    /*private ProxyFactory(){

    }

    private static ProxyFactory proxyFactory = new ProxyFactory();

    public static ProxyFactory getInstance() {
        return proxyFactory;
    }*/


    /**
     * Jdk动态代理
     *
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Object result = null;
                        boolean needTransaction = false;

                        List<Annotation> annotations = new ArrayList<>(16);

                        Method declaredMethod = obj.getClass().getDeclaredMethod(method.getName(), Arrays.stream(args)
                                .map(Object::getClass).toArray(Class[]::new));

                        annotations.addAll(Arrays.asList(declaredMethod.getDeclaringClass().getDeclaredAnnotations()));
                        annotations.addAll(Arrays.asList(declaredMethod.getDeclaredAnnotations()));
                        for (Annotation annotation : annotations) {
                            if (annotation.annotationType().getName().equals("com.lagou.homework.annotation.Transactional")) {
                                needTransaction = true;
                                break;
                            }
                        }

                        if (needTransaction) {
                            try {
                                // 开启事务(关闭事务的自动提交)
                                transactionManager.beginTransaction();

                                result = method.invoke(obj, args);
                                // 提交事务
                                transactionManager.commit();
                            } catch (Exception e) {
                                e.printStackTrace();
                                // 回滚事务
                                transactionManager.rollback();

                                // 抛出异常便于上层servlet捕获
                                throw e;
                            }
                        } else {
                            result = method.invoke(obj, args);
                        }
                        return result;
                    }
                });

    }


    /**
     * 使用cglib动态代理生成代理对象
     *
     * @param obj 委托对象
     * @return
     */
    public Object getCglibProxy(Object obj) {
        return Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Object result = null;
                boolean needTransaction = false;

                List<Annotation> annotations = new ArrayList<>(16);

                annotations.addAll(Arrays.asList(method.getDeclaringClass().getDeclaredAnnotations()));
                annotations.addAll(Arrays.asList(method.getDeclaredAnnotations()));
                for (Annotation annotation : annotations) {
                    if (annotation.annotationType().getName().equals("com.lagou.homework.annotation.Transactional")) {
                        needTransaction = true;
                        break;
                    }
                }

                if (needTransaction) {
                    try {
                        // 开启事务(关闭事务的自动提交)
                        transactionManager.beginTransaction();

                        result = method.invoke(obj, objects);
                        // 提交事务
                        transactionManager.commit();
                    } catch (Exception e) {
                        e.printStackTrace();
                        // 回滚事务
                        transactionManager.rollback();

                        // 抛出异常便于上层servlet捕获
                        throw e;
                    }
                } else {
                    result = method.invoke(obj, objects);
                }
                return result;
            }
        });
    }
}
